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Different grades of Acid-fast Bacillus (AFB) smear microscopy and its results are as follows:

Tuberculosis is caused by Mycobacterium tuberculosis which is a unique acid-fast gram-positive bacterium.

It is unique because of the high lipid and mycolic acid content of its cell wall. It neither contains the phospholipid outer membrane, nor retains the dye. 

Acid-fast Bacilli (AFB) Microscopy identifies tubercule bacilli and hence is used under National TB Elimination Program (NTEP) for:

All healthcare workers need to take the following precautions while undertaking the TB diagnostic specimen collection, transportation and receipt of samples as TB is an airborne infection:

The criteria for acceptance and rejection of TB specimens at TB Diagnostic Laboratories are listed below:

Acceptance Criteria:

• Sample received in triple layer with no leakage
• Sample is without any blood and food particles
• Sample is received within 48 hours expected timeline after collection in a cool chain
• Adequate label and information about the specimen
• Identical name on the specimen and in the test request
• Sample is in adequate quantity

Rejection Criteria:

There is a specific procedure prescribed under the National TB Elimination Program (NTEP) during receipt of the specimen for NTEP Laboratory.

At the laboratory, all specimens need to be received in the registration area.

To minimize the risk of infection, the following procedures should be applied:

Some logistics should be available in all National TB Elimination Programme (NTEP) laboratories so that biological samples including sputum can be correctly transported to nearby Culture and Drug Susceptibility Testing (CDST) laboratories. The logistics required for packaging biological specimens are: 

One of the human resources required in the Intermediate Reference Laboratory (IRL) is the Senior Laboratory Technician (LT). 

The Terms of Reference (TORs) of the Senior LT are: ​

Children younger than 10 years form one of the important vulnerable groups for Tuberculosis.

The vulnerable children under 10 years are categorised into the following three main categories and they are screened differently for TB (Figure).

Under the National Strategic Plan (NSP) 2020-25, systematic screening of high-risk groups through outreach and community-based approaches using digital X-rays and rapid and more sensitive diagnostic tools is planned via:

Screening for active tuberculosis (TB) should be done with a tool that:

• Effectively identifies people who probably have active TB
• Has high sensitivity (very high specificity is not necessary for a screening tool)
• Needs to be inexpensive
• Should be feasible to use in a given setting
• Is acceptable to a given risk group.

Options for the screening for TB include: